(CNN) -- The actions of a South Korean soccer player barred from receiving his Olympic bronze medal after he displayed a politically-charged banner were "not intentional", the country's football body said on Monday.
The Korean Football Association (KFA) said Park Jongwoo did not receive his medal after his team's win over Japan at the request of the International Olympic Committee (IOC), which prohibits political statements by competitors.
Midfielder Park was photographed after Friday's match holding a sign with a slogan supporting his country's sovereignty over a disputed island chain that is also claimed by Japan.
An official from the KFA said that it had been asked to investigate the case by FIFA, soccer's ruling body, and submit its results by Thursday.
"It is proven from photos that Park's action was not intentional. He didn't make the sign," the official told CNN.
"As you can see from photos, a fan was holding the sign during the match and Park got it from the fan."
The official said it was still unclear whether Park would receive his medal as the investigation was still ongoing.
Many in South Korea have criticized the decision, with the English-language paper The Korea Times asking whether the IOC had overreacted.
If Park does not receive his medal, he may not be exempted from compulsory military service -- a benefit accorded to Olympic medal winners in South Korea.
The incident has also heightened a tense diplomatic standoff between Japan and South Korea.
Last week, South Korean President Lee Myung-bak visited the tiny islands that are known as Dokdo by South Koreans and Takeshima by Japanese.
On Friday, Japan recalled its ambassador to South Korea and threatened to take the dispute to the International Court of Justice.
South Korea has police officers stationed on the islet, media reports said, while Japan's foreign minister, Koichiro Gemba, said that the islands were "an inherent territory of Japan, both in the light of historical facts and based on international law."
Dokdo /Takeshima is one of several of disputed island chains in the region and fears are emerging that competing territorial claims in the South China Sea could create a new Cold War in Asia.
China, Vietnam, the Philippines, Malaysia, Brunei and Taiwan all have claims in the area and tensions have risen in recent months.